Liquid process for manufacture of motor fuel



Dec.-Z, 1.941. w, c, AsBURY 2,264,427

LIQUID PROCESS FOR MANUFACTURE OF MOTOR FUEL' Fil'ed May- 20, 1938 .DRUM

GAS 00715-7' RlcllY/NG Patented Dec. 2, 1941 2,264,427 q LIQUID rnocEss ron MANUFAcrUnE oF Moron FUEL Willard c. Asbury, London, England, assignor to Standard Catalytic Company, a corporation of Delaware Application May 20, 1938, Serial No. 208,989

Claims.

The present invention relates to the art vof producing valuable hydrocarbon fuels from less valuable carbonaceous materials, and more specically to the improved method for synthetically producing fuels for internal combustion engines. The invention will be fully understood from the following description and the drawing.

'Ihe drawing is a semi-diagrammatic and sectional elevation of an apparatus adapted for carrying out the present process and indicates the ow of materials therethrough.

One object of thepresent process is to produce a high grade motor fuel or gasoline from waste carbonaceaus materials. While some such processes are now known in the art, it is also known that the products obtained therefrom are poorly suited for the present day engines, first because of the unstable character of the fuel, but mainly because of theirextremely poor antidetonation characteristics. It is found that the application of the present process corrects to a large degree the faults of prior processes as will be understood from the following description.

Turning to the drawing, the numeral I, designates a pipe through which waste hydrocarbon gas is supplied. This may be a natural gas, a petroleum gas, cracked gas, coal gas or the like. It is first subjected to desulphurisation indicated generally at 2. The particular process employed should be adapted to the particular raw material, and the choice may be made between many known processes by which organic sulphide and hydrogen sulphide are removed. The gas may be passed over ferrous sulphide, for example, and then a scrubbing liquid capable of absorbing hydrogen sulphide. The puriiied gas then passes by a pipe 3 to a converter 4, wherein hydrocarbon gas is caused to react with steam which is supplied by a pipe 5. The reaction is carried out at a temperature above about 1200 F. and is promoted by catalysts containing nickel or cobalt. Excellent catalysts may be made by absorbing nickel or cobalt salts such as the nitrates in magnesia, alumina or bauxite, and then reducing the salt to the metal by heat. The conversion process results in the decomposition of the hydrocarbon and produces a mixture of hydrogen, carbon monoxide and carbon dioxide, the proportion of the latter being decreased by raising temperature and reducing the amount of excess steam.

The conversion gas is now treated to separate the CO2 and for this purpose any known process may be employed, for example, the gas may be cooled and scrubbed with liquid materials capable of dissolving carbon dioxide from the gas mixture. As scrubbing agents sodium carbonate, triethylolamine, amino-propanol and the like may serve as examples. As illustrated in the drawing the gas passes through the tower 6, and is scrubbed therein by the absorption liquid which enters by means of pipe 1, and passing through the tower absorbs the carbon dioxide and leaves from the bottom of the tower 6, by a pipe 8. Pump 9 passes the liquid to a stripping tower IIJ, which may be supplied with heat indirectly or may be heated by the direct addition of steam so as to remove the absorbed carbon dioxide and to regenerate the scrubbing liquid which is returned to the tower I by the pipe Il.

Carbon dioxide thus recovered may be advantageously collected in a pipe I2a and passed along with such additional quantities thereof (by pipe I2b) as may be required to pipe 3, so as to enter the converter 4 along with the hydrocarbon gas and steam. The object of this addition to the gas undergoing conversion is to produce a more favorable ratigipf carbon monoxide to hydrogen, than 1s obtafd by the use of the hydrocarbon gas and steam alone. When steam alone is employed with gases consisting principally of methane the ratio of carbon monoxide to hydrogen produced by reaction approximates 1 to 4 and it is preferred to add a sumcient amount of carbon dioxide to change this ratio Vto about 1 to 2.

The synthesis gas is now removed from the scrubbing tower 6 by pipe I2 and is compressed in a pump I3 for use in the subsequent step. It will be realized that the method described above is particularly adapted for use with hydrocarbon gas but, if hydrocarbon gas is not available, other carbonaceous material maybe employed, for example, coal or coke may be converted with steam or a mixture of steam with carbon dioxide to produce the desired mixture of carbon monoxide and hydrogen using the equipment employed in water gas production. It is important to adjust the ratio of gases, so as to approximate one part of carbon monoxide to two of hydrogen however, and when both coal and hydrocarbon gases are available this may be conveniently done by separately converting each with steam alone and then admixing the converted gas in the proper proportions.

Whatever the process, by which synthesis gases are produced, they are now compressed, as

dnnn l1. Theunconvertc'dgasesarewithdrawn bythepipe I8. Itispreferabletounployrates of ilow and other conditions, familiar to the art,soastoobtainfmm40to60% converslonof the gas in the reactor II. 'Ime specic conditions varysomewhat withcatalysmbutaregenerallyknownandmybereadily The remaining gas is tlm posed through a second heater I9,aseccndconverter2l andinto a separator 2l, so as to substantially complete theconversionofthesynthesisgas. Theequipment just described is idemilca with the heater, the converter and the separator y previously described. The temperature and pressure conditionsarelikewisethesame. Theliquid product is drawn oi! and the gases comprisingunconvertedcarbonandhydmgen together with` are seporatedfromtheliquidandarewithdrawntmma pipe22. Thesegasesmayberecireulatedtoa converterlortheymayberetumedtoheaters liorll. 'Ihepipesvslvesandor these variations, arenot shown m1 the drawing. for simplicity,bnttheoperation,wll1bereadily Theliquidproductiswithdrawfromtheseparators l'l and 2l andmaybeadmixedandpassed intoatowerstill. Thematerlalsobtainedin eachofthestagofthesynthesisaresuhstantiallythesameoflowerboilingh'actions boiling up to about 400 F., and fractions boiling above that temperature. It desired. the light distillate boiling below about 400 F., may be taken overhead and collected in the receiving chamber 2l, gas removed by 25 and the liquid recovered at 25a. The residueis then posed by a pipe 2i and pump 26a to the Subsequent operations of this process. If dired, however, the separation of the light and heavy fractions need not be made, and in this case tbe entire liquid product may be withdrawn from the drum I1 and 2| and passed by a lay-pas line 28 directly into pipe 2S thence into furnace 21, and thereafter into reaction chambers 2! and 29a.

'Ihenatureoftheliquipmductproducedin the conversion chambers li and Il will vary somewhat with the operating If the pressureislomebehwabont the product is substantially hydrocarbon. and there is a relatively larger proportion of lower boiling to higher boiling fractions. It is preferredto operatethepresmtprocessathigher pressure,say,1to50andinthis condition the product contains a relatively larger proportion of fractions boiling above 400 F. It is alsofoundthatthematerialpmducedinthis drocarbonsoftheglsdirebdlhlnnkhkm od'bythevaporllpeJscooledarllcdhdcd indrumLhomwhichthegasisxplntedh! notbeexceedcdasabonthklint 'produceapermanmtdeteriaatindnechm Anothersuitnblecatalystcanbemadelutreatmentofnatmalclayasnchasbentmitmnmtmorillonitesandthelewithmheralmmdr as hydrochloric, and sulplmic. Suchmaterialsaresoldundermanytnrbnames andusedwhielyiorlntlicatingdk. Stillothercatalystsmaybellwlmdnnldicallybymecipitationofsilicaintbegclfmm. Thematerialisthmhydxatedbyheat. l-

'icamaybeusedakmeoritmaybeadmixedor preparedbysimultaneopredlitaonwithdhergelpariicularlyalumina.

Theabovementmxedcatalystswhkharedescrihedbroadlyasactivesliceouscatalystsmay beemployedambuttheymllalmbefurtin activatedbytheadditionofother partlcularlybytheadditionotmetalommch asnickelorcobaltoxidesmanganesenxlhor oxidesofthetthandsixthgrm. 'Ihecmversionstepiscarriedoutatadeonminnperatmeemabout'lwtoll'lorperilps 9501".,andpretaablyatalowpresmre,m Snphrprmrcupiowve Therateofowmayvaryconsidenbbdemdingupontheparticularcatalystandtanpmime and other 'Ihelencthofmnalsn dependsonthenatureottheoilandthecmatonsofoperatiombutitkordmsrib" trmnzhvl hoursmoreorlembefore reservation' isrequired, this is made manifest by the gradually decreasing conversion. It has been found desirable not to let the activity fall too low before regeneration, because this requires an excessively long period for regeneration. It is preferred to use air diluted with steam or other inert gas for the regeneration, this is accomplished by passing the gas through the catalyst at a temperature up to about 1000 or 1200 F., at which temperature the carbon may be burned oif without spoiling the catalyst. By the time the catalyst in the converter chamber 28 has deteriorated, the material to be converted may be passed through the chamber 29 now ready for use, and the regenerating gases may be passed through chamber 28. In this way, one of the chambers will be continually in use, while the other is being regenerated.

The present process is particularly advantageous because of the high yield and excellent quality of the products. Gasoline obtained directly by the reaction of a mixture of carbon monoxide and hydrogen, is poor in quality particularly from the anti-detonation standpoint, and the present process presents a great advantage in this respect, in that a relatively small amount of gasoline may be produced in the initial synthesis step along with a major quantity of higher boiling material. This latter material is converted into gasoline in the subsequent` step and is found to be of superior quality in respect l to stability and anti-detonation quality. While it is not necessary to this invention to'produce an intermediate product containing oxygen, it is preferred to operate under such conditions because a material of this type has a marked advantage in the subsequent steps of the process in which the higher boiling material is converted to gasoline and is simultaneously deoxygenated. It is observed that simultaneous conversion and deoxygenation favorably influences the anti-detonation characteristics in the product.

To illustrate the nature of the present process and the advantages of the present known process, the following may be considered.

Example 1 A mixture of carbon monoxide and hydrogen, consisting of one part of the former to two of the latter was converted in the usual manner with a pressure of two to three atmospheres and at a temperature of 350 F.using a nickel catalyst. The product obtained comprised about 50 to 60% of gasoline and 40 to 50% of heavier liquid, depending on the fractionation and type of gasoline cut. The gasoline Was exceptionally light and had the following characteristics:

Gravity A. P. I 71. 6 Percent at'158" F percent 28.0 Percent at 212 F do.. 53. 0 Percent at 257 F -don- 71. 0 Final boiling point '.F 376 The octane number of the product was found to be 57 clear and an analysis showed that it had a bromine number of '71. The material was essentially a mixture of parain and olene hydrocarbons.

The gas-oil fraction of the product had a gravity of 51. 3 A. P. I., an aniline point of 119, an initial boiling point of 308 F., 50% boiled over at 510 F. and it had a final boiling point of 740 F. This gas-oil was converted at a temperature of 870 F. using a flow of .55 volume of oil per volume of catalyst per hour. The catalyst was an acid treated clay of the montmorillonite type. 'I'he yield of gasoline obtained in this way amounted to 41.4% and 49% of gas-oil remained,

. which could be converted in the subsequent Cil operation. The gasoline had the following characteristics:

4It will be noted that this material had a better boiling curve than gasoline directly produced in the previous step, it also had an octane number of 74.2 clear.

Example 2 In the second experiment the conditions of operation were changed as follows: l

The pressure was increased to about 20 atmospheres, the temperature raised to 600 to 625 F., an an iron catalyst was substituted for the nickel catalyst previously used. The yield of oil obtained in 'the conversion step was substantially the same as that obtained in the previous example, but it was observed that the proportion of gasoline obtained was decreased to about 40%, and the proportion of gas-oil was correspondingly increased to about Inspection also showed that the gas-oil contained a mixture of oxygen compounds of unknown constitution to the extent of about 2.5% land was not stable as such.

The gas-oil fraction was then cracked under identical conditions of the prior example with substantially the same yields. The distillate product or gasoline was completely free from oxygen compounds and had an improved octane number.

The present invention is not to be limited to any theory of the operation nor to the chemical reactions believed to have taken place, nor to any specific conditions or catalysts, but only to the following claims to which it is desired to claim all novelty adherent to the invention.

I claim:

1. An improved process for manufacturing motor fuel comprising the step of directly reacting carbon monoxide and hydrogen at a temperature between 475 and 650 F. while under pressure of about 1 0 to 50 atmospheres, with a catalyst comprising iron, whereby an-oxygen containing liquid is produced, then treating a portion of the product so obtained at a temperature between about 700 to 950 F., in the presence of an active siliceous catalyst, whereby the material is deoxygenated and converted into an improved motor fuel.

2. Process according to claim 1, in which the intermediate liquid material first produced is separated into lower boiling products, and products boiling above the motor fuel range, and in which the latter fraction alone isv subjected to the second reaction step.

3. Process according to claim 1 in which the second step is carried out at a pressure between atmospheric pressure and five atmospheres.

4. An improved process for manufacturing mo-v tor fuel comprising the steps of producing liquid organic material by direct reaction of carbon monoxide and hydrogen at temperatures from about 475 to 650 F. while under a pressure between about 10-50 atmospheres with a catalyst comprising iron, whereby substantial amounts of hydrocarbon boiling above 400' F. are produced, then treating the liquid at a decomposing temperature in the presence of an active siliceous catalyst.

5. An improved process for manufacturing motor fuel comprising the steps of producing liquid organic material by direct reaction of carbon monoxide and hydrogen at a temperature of approximately 60G-625 F. while under a pressure of approximately 20 atmospheres with a catalyst comprising iron, then treating the liquid at a de composing temperature in the presence of an active siliceous catalyst.

WILLARD C. ASBURY. 

